Trzcinski Natalie K, Hsiao Steven S, Connor Charles E, Gomez-Ramirez Manuel
National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD, USA.
The Zanvyl Krieger Mind/Brain Institute, The Johns Hopkins University, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins School of Medicine, Baltimore, MD 21218, USA.
Cell Rep. 2023 Mar 28;42(3):112176. doi: 10.1016/j.celrep.2023.112176. Epub 2023 Mar 2.
The leading view in the somatosensory system indicates that area 3b serves as a cortical relay site that primarily encodes (cutaneous) tactile features limited to individual digits. Our recent work argues against this model by showing that area 3b cells can integrate both cutaneous and proprioceptive information from the hand. Here, we further test the validity of this model by studying multi-digit (MD) integration properties in area 3b. In contrast to the prevailing view, we show that most cells in area 3b have a receptive field (RF) that extends to multiple digits, with the size of the RF (i.e., the number of responsive digits) increasing across time. Further, we show that MD cells' orientation angle preference is highly correlated across digits. Taken together, these data show that area 3b plays a larger role in generating neural representations of tactile objects, as opposed to just being a "feature detector" relay site.
体感系统中的主流观点认为，3b区是一个皮层中继站，主要编码限于单个手指的（皮肤）触觉特征。我们最近的研究对这一模型提出了质疑，研究表明3b区的细胞能够整合来自手部的皮肤感觉信息和本体感觉信息。在这里，我们通过研究3b区的多手指（MD）整合特性，进一步检验这一模型的有效性。与普遍观点相反，我们发现3b区的大多数细胞具有延伸至多个手指的感受野（RF），且RF的大小（即有反应的手指数量）会随着时间增加。此外，我们还发现MD细胞的方向角偏好在各个手指间高度相关。综上所述，这些数据表明，3b区在生成触觉物体的神经表征方面发挥着更大的作用，而不仅仅是一个“特征检测器”中继站。
